getting files to kindle for me this summer vacation 2-3 weeks ago was major PITA, I took kindle for kid and first USB cable in drawer unaware that this particular USB cable is only for charging and can't do data transfer, since i use only USB C and kindle doesn't support it
my kindle has no amazon account, because I am sideloading everything offline, prety much not using anything online on kindle
so when I figured out the problem is USB cable and registering amazon account would be too troublesome I discovered you can't send files to kindle simply over wifi direct or bluetooth or other simple way and I end up downloading legally obtained books from my library first to my laptop from where I connected to FTP server launched in Mixplorer in my Android phone, transferred through there books to phone, then again launched in mixplorer in phone HTTP server since kindle doesn't support FTP connection, typed IP address in experimental kindle browser and et voila I could finally see files I wanted to read on Kindle, only problem was despite the format supposedly supported by Kindle, when I tapped on file it shown me error the file is not supported for download through kindle browser (despite supported if you sideload it through data cable), so I had again convert these PDF/EPUB/AZW or whatever files in calibre to MOBI, again transfer to phone, then again transfer to kindle, where finally after tapping files were downloaded and I could finally read story to my kid, can't imagine how regular user would be able to transfer books to kindle without data cable and amazon account and if their transfer service stops supporting certain format then only option for regular user is data cable
TIL Calibre has own web/content server which should be accessible from Kindle experimental browser, so could save myself trouble transferring files back and forth through mobile
my kindle has no amazon account, because I am sideloading everything offline, prety much not using anything online on kindle
so when I figured out the problem is USB cable and registering amazon account would be too troublesome I discovered you can't send files to kindle simply over wifi direct or bluetooth or other simple way and I end up downloading legally obtained books from my library first to my laptop from where I connected to FTP server launched in Mixplorer in my Android phone, transferred through there books to phone, then again launched in mixplorer in phone HTTP server since kindle doesn't support FTP connection, typed IP address in experimental kindle browser and et voila I could finally see files I wanted to read on Kindle, only problem was despite the format supposedly supported by Kindle, when I tapped on file it shown me error the file is not supported for download through kindle browser (despite supported if you sideload it through data cable), so I had again convert these PDF/EPUB/AZW or whatever files in calibre to MOBI, again transfer to phone, then again transfer to kindle, where finally after tapping files were downloaded and I could finally read story to my kid, can't imagine how regular user would be able to transfer books to kindle without data cable and amazon account and if their transfer service stops supporting certain format then only option for regular user is data cable